Soak mute "bug"

In various posts a couple of us have encountered a strange situation whereby the gm40d on changing preset trips the amp into the power soak mute condition. The yellow lamp at the back is triggered and the apparent workaround is to press the button and the amp restores itself.

It's been suggested that this only happens on the first midi programme change, if so and it doesn't repeat then as part of your pre flight checks at a gig you could send a pc, via a midi changer and call out a preset say then when the bug appears simply override it by pressing the yellow lamp.

I lodged a ticket with h&k on their website and the representative from jhs in the uk suggested after I provided the serial number that it was an early release and that I should send it back to the supplier (Thomann in Germany) for swap out. Thomann are saying it's a repair and that they'll send it to h&k, it could be away for a month.

So naturally I am not delighted by the prospect but hate things not working as they should.

However before I go down that route I thought I'd try and identify what's happening and what is not. For me this appeared whether the iPad app was connected or not.

What I have noticed that I can replicate the issue if I change the amp channel on the app but it ONLY happens if the preset is one that I've created (saved and stored to a new location above the factory presets i.e. 91 and up). I stepped through all 90 presets and not one of my factory presets triggered the condition.

I then found that if I entered say preset 91 and saved it again the bug did not appear again, whether I called it from my midi switcher OR manually. Also I can force the condition if I select an empty preset (for me just now from 102 and up).

I've power cycled the amp and reconnected the app and it seems to be fixed but only for the newly created presets not the empty presets...

I have never taken a backup of the presets but did so and saved back to the amp, now all of the other affected presets seems to have righted themselves and the power soak may bug is no more. (Apart from the empty presets that is)

I'm not entirely convinced.

I'll try and break it again tomorrow but is the issue perhaps related to how the presets are saved? Not sure if I created these presets from a factory preset when the global power soak was enabled perhaps and now it's off the amp is protecting itself/ or the user perhaps?

Can someone try selecting an empty preset and confirming that the power soak mute is enabled?

Perhaps this "bug" is simply operator error?

Let's hope so, but I might still try and talk to h&k technical not just their handling agent in the U.K. And see if they'll divulge just what the firmware update actually does....

Just trying to get my head around the logic of what you are describing George, and I'm not a GM40 user, but logic is logic....

Could I suggest you save your presets to file in a state where this will happen on some of them, that may mean creating a couple of dummy ones at the top end, and post it here. We can look inside the file to see if anything in there is unusual. If it is eradicated once the patch is saved to file and loaded back from it this could be visible in the file data after that first save.

The other possibility is that it may be in the initial settings stored in the amp in the unused top end patches. It may possibly be solved by loading the amp up with a dummy file of a completely full set of patches made by copying one of the factory ones which doesn't cause the problem multiple times. Follow that by reloading up your working patch file set and we may have copied over whatever is wrong in the "above factory" ones.

Hi Bordonbert, yep I follow. Where i will fall down however is extracting the files from the ipad app and how to post here?

That said, i guess i can fire up the laptop and get Fredo's the desktop app working. I might have time tonight to have a look at this.

It should be relatively straightforward as the "bug"/"feature"/"whatever" occurs on ALL empty presets in the list and any presets created from factory defaults.

I take it that I am saving the preset correctly?

So say i want to save a version of preset 24 to position 108, I press the "save" button on the app then press the app list and select a new position, a pop up appears summarising all the parameters in the preset 24 and asking whether I want to save it to the new position selected, in my example 108. I click yes.

So it saves a modified version of factory preset 24 to position 108. Now when i select any other factory preset all works as normal, however if i then (via the app) select position 108 then the power soak mute is selected.

The power soak mute function disappears once and for all only after save preset 108 again (to postion 108). Hope that's clear.

(i will probably go home tonight and try this and the bloody thing wont happen!).. lets see how it goes.

I think if you output it via any of the apps available it should be ok. If you can make sure there will be at least one problem patch on the end and let us know which one when you post it up we should be able to have a look inot the file to see what's what. It may come to nothing but there just might be something obvious in there.

And thanks for the really clear description of how the problem can occur and can be cleared, I'm not used to getting such straightforward info on forum pages! A simple couple of minutes preparation saves another 5 or 6 posts backwards and forwards asking for clarification.

If you use the [Add Reply] button rather than the Quick Reply box you will find an "Attach File" section below the edit window. Use the [Browse] button to select the file and I think the [Submit Query] to upload it, (or something similar). It would help if you popped the file into a .zip folder first as the upload system might not accept the raw format your app will spit the data out in.

Hi BB, so as luck would have it and true to form, i can now not replicate the above issue.

The Empty Presets of course still take the amp into the power soak mute condition but i can see this makes some kind of sense.

The only thing i can think of, and now its done i cannot roll it back is that after spending some time the other evening isolating the conditions which enabled the mute soak function that I saved the presets back to the Amplifier, something which i had not done previously.

I am now confused, so its back to basics and i will attempt to replicate the issue.

At present i am happily working via my Boss ES-8 as the midi switcher and running through two fairly Midi intensive sets of about 30 tracks and there is absolutely no failure at all.

Of course in describing my original point i was NOT involving the es-8, i was merely calling the presets via the iPad app and noticed that ONLY those presets that I had saved from factory defaults triggered the mute soak condition every time until they themselves were saved.

Ho hum, i haven't had time to ask H&K technical details of their recent firmware update but if i have no issues then i am loathe to send off a working amplifier for what could be the best part of a month to Germany, unless of course that update offers serious improvements in performance or stability somehow.

If I can replicate the issue I will come back to you (if thats ok?) and provide an update.

If anyone is reading this with a GM40, can you just to be sure fire up your amp and app please and select an empty preset and confirm that yours too does indeed default to the Mute Soak condition please? (fairly sure it will).

No problem JG, I know how these things can go. The gods of electronics are just not with you at the moment. If you find you can replicate the issue then stick the file up here any time and I'll have a look at it.

From what I remember Fredo's Windows app still spits data out in plain text format, (as they all really should). If you get it as the GM40 equivalent of a '.GM36' format file, ('.GM40' format?), you can simply rename the file to '.txt' and open it up with any text editor. A tip here is that, if you want to edit the file manually, you should stick to something very simple like Notepad as that would resave the file with the line endings in the same format. If you use Wordpad or Word it adds additional characters to get its line feeds which screws with the file contents for reloading into the amp.

The iPad app, being crApple ( ), won't let you see the contents of your own file!!! It saves into Apple's XML equivalent, '.plist'. This needs a special viewer as it is a binary format which only the machine knows how to interpret. There are free viewers out there but even with them, if you are not used to viewing in that layout it's a stinker to read through and get to the meaning of the content easily. Fredo has exactly the right approach for the circumstances!

If there is anyone else out there who can spit out a version of their patch file with some faulty patches in it which replicate the power soak issue, it would be really helpful for us to see if there is anything relevant in the file. Guys?.......

Well after a fairly intensive weekend of midi switching and also manually changing presets via the ipad APP, i cannot get the soak mute to appear at all! I am delighted.

This was a solid fault for me but it appears that it might have been down to the way that the presets were saved in the app and when i loaded them all back down to the amplifier the "condition" which any of the offending presets had was overwritten.

Still looking for someone to confirm to me that when the select an empty preset on the ipad app that the soak mute is triggered. I think this is a protection for the user and the amp and its not a problem in any way.

I would suggest any other users who change presets using midi (or manually), if your GM40D goes into this state to save all the presets down to the amplifier. This seems (on the face of it at least) to have resolved my issue.

I can now get back to concentrating on playing guitar and rocking the hell out of the thing!

j200george wrote:It's been suggested that this only happens on the first midi programme change, if so and it doesn't repeat then as part of your pre flight checks at a gig you could send a pc, via a midi changer and call out a preset say then when the bug appears simply override it by pressing the yellow lamp.

I had that idea, but in reality it would not work. About the muted presets, I cannot recall that with the app connected, the amp went into mute mode, at least not like in the fashion with no app connected (1st midi in = 0Watts).

Another user reported that if he has a tuner in the preamp out the problem would not occur, I dont have the amp right now (replacement incoming) to test this myself.

Nevertheless thanks for your efforts and I'm glad you got it to work and many will be thankful for your findings too, george

Aenima wrote:Another user reported that if he has a tuner in the preamp out the problem would not occur

I know it's only what has been reported elsewhere and not your own observation Aenima but that sounds a bit far fetched to me. Unless they've changed it radically for the GM40 the Preamp Out is a totally separate isolated part of the circuitry which is just a dedicated opamp buffer straight to the socket. The only affect (Edit: Damn it! Should have been Effect. ) of hooking up a tuner would be having that opamp lightly loaded on its output. Anyone could perhaps test that with just a resistor as a load.

I have to say I really think that will prove to be a bit of a blind alley. The only way I can see that being linked to the problem is through a bad PCB or wiring fault which has slipped through, the Preamp Out is not involved in the programming or the control circuitry in any way. Is it possible for someone to try it with a tuner to either prove or disprove it? This has the smell of a programming fault and may well be sorted with H&K releasing (very quietly) a firmware update. It may also be the case that it has an easy workaround which only needs to be applied once. I would still be interested to see what happens once the amp has been filled with valid patches overwriting the ones which are there from the factory, (even the blank spaces at the top end). I would hope that would remove whatever residual issue is causing the fault. It could be interesting to see a dump of the file with the fault still showing itself. There may just be something we can see there.

Last edited by bordonbert on Wed Apr 05, 2017 4:29 am; edited 1 time in total

Probably he was refering to another problem. he did not answer my question for what he did use this. Maybe only to get the tuner out of the signal chain, so I second your opinion. I should not have mentioned it, before knowing if he was refering to the mute problem, that was discussed in that same thread where he posted.

I'm getting my replacement tomorrow. I'm eager to know if I will get the latest firmware..

Still no fault and I played solidly for three hours on various presets calling several PC's to do so.

All I can offer now would be to export my back up file with the empty presets which all, when selected, force the amp into mute soak. I'll do that if someone with a gm40 reports that their unit acts differently.

Might be a delay though now as I'm off to Chamonix tomorrow.

I had a hard fault. It's gone and it appears that saving all presets to the amp resolved it.